Within the context of the present invention, ‘means for life-saving’ is understood to designate any means provided for rescue, life-saving and survival at sea which is able to be launched into the water, such as in particular rescue boats, lifeboats and, most particularly, containers containing an inflatable life raft in the uninflated and folded state or any other similar device (for example, a rescue platform) designed to be implemented by being launched into the water within the context of life-saving at sea.
The means for life-saving or survival at sea are usually fitted in ships or fixed installations such as offshore platforms, for example for oil drilling. The means for life-saving or survival are often arranged at significant heights above the water, for example on an evacuation deck able to be located at a height of 20 metres or more on ships, or at even greater heights, of 30 or 40 metres, even 50 metres, on fixed platforms.
The means for life-saving or survival, whatever their type: rigid (such as a boat) or pneumatically inflatable, contained in a container and which are designed to be launched into the water, have to be launched without damaging the structure itself or the equipment with which they are fitted.
The greater the drop height and the greater their weight, the more violent their impact with the water, which for large drop heights, results in substantial reinforcement of the life-saving means with regard to its mechanical resistance to impact, solely from the point of view of its launch into the water.
This is the case, in particular, for inflatable life rafts of relatively large capacity (for example 25 to 50 people) or large, even very large, capacity (for example 80, 100 or 150 people), which are, in particular, fitted to passenger-carrying ships (liners, car ferries) and which are contained in the uninflated and folded state with their equipment in a rigid, mechanically resistant container, for example of generally cylindrical shape, which is stowed on a deck of the ship. A container containing a large capacity raft (several dozen people) weighs several hundred kilos (and even considerably exceeds a tone for very large capacity rafts of 100-150 people).
At the moment of impact of the container with the water, the violence of the impact may cause delamination of the layers of fiberglass and/or break-up of the constituent resin of the shell of the container, even the rupture of the shell of the container. This deterioration leads to the formation of sharp fragments and sharp edges capable of piercing the flexible wall of the float of the raft during the inflation thereof.
This has led manufacturers to produce containers which have even greater reinforcement (and are therefore even heavier) by increasing the fiberglass and resin layers, the greater the anticipated launch height, and to define a maximum launch height (or nominal launch height) which the container has to be able to resist without damage.
As the increased mechanical resistance of the container is translated into a significant increase in cost, users generally wish to use containers approved only for a drop height which is strictly necessary, for optimum reduction in the cost of fitting out ships. These requirements lead manufacturers to increase the number of types of container approved for various launch heights, which poses problems for manufacture and the stocking of parts, and even maintenance. All things considered, increasing the number of different types of container does not allow their cost price to be reduced as much as would be desirable.
There is therefore a constant demand on the part of manufacturers and users and ship owners, for a greater standardization of containers for life rafts and more generally for a reduction in weight of all life-saving means whatever the type, whilst respecting the restrictions to the speed with which they come into contact with the water when they are launched, in order to avoid damage thereto.